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Egr-1(early growth response-1)系-具有辐射诱导特性的转录因子.其调控序列被证实可通过与肿瘤杀伤基因相连接的方法而赋予后者以辐射诱导特性,因而被用于肿瘤的基因-放射治疗研究.为此,我们用PCR方法从BALB/c小鼠基因组DNA扩增出445bp长Egr-1基因调控序列,序列分析证实,除-392位一个碱基(A→G)相差外,其余均与文献报道一致,包括6个对辐射诱导特性起关键作用的CC(A+T)_6GG结构域-将克隆的Egr-1基因调控序列连入pCL3荧光素酶报告质粒,转染小鼠恶性黑色素瘤细胞(B16),转染细胞用~(60)Coγ-线进行2.5、5.0和10.0Gy不同剂量照射后,检测细胞裂解液中荧光素酶活性.与未照射细胞比较.照射后细胞荧光素酶活性明显提高,以2.5Gy剂量最为显著.提高约138%,表明Egr-1基因调控序列具有辐射后诱导下游基因表达的功能.
Egr-1 (early growth response-1) is a transcription factor with radiation-inducing properties. Its regulatory sequence has been confirmed to be able to impart radiation-induced properties to the latter through a method linked to a tumor killer gene. Gene-radiotherapy studies. For this purpose, we used PCR to amplify 445bp Egr-1 gene regulatory sequences from BALB/c mouse genomic DNA. Sequence analysis confirmed that there was a difference in one base (A→G) except -392. In addition, the rest are consistent with the literature reports, including six CC(A+T)_6GG domains that play a key role in radiation-induced characteristics - the cloned Egr-1 gene regulatory sequence is ligated into the pCL3 luciferase reporter plasmid, transfected Mouse malignant melanoma cells (B16), transfected cells were irradiated with different doses of ~(60)Co?-ray at 2.5, 5.0, and 10.0 Gy, and luciferase activity in cell lysates was measured. Compared with unirradiated cells. After the cell luciferase activity was significantly increased, with 2.5Gy dose was the most significant increase of about 138%, indicating that Egr-1 gene regulatory sequence has the function of inducing downstream gene expression after irradiation.